GCN Circular 33576
Subject
GRB 230405B: Swift/UVOT Upper Limits
Event
Date
2023-04-06T08:06:53Z (3 years ago)
From
Samantha Oates at MSSL <samantha.oates@alumni.ucl.ac.uk>
S. R. Oates (U. Birmingham) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 230405B
75 s after the BAT trigger (Page et al., GCN Circ. 33571).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 33574)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 75 224 147 >20.5
u_FC 287 537 246 >19.7
white 75 1363 373 >20.7
v 618 4860 274 >19.1
b 542 1339 78 >19.0
u 287 1313 304 >19.7
w1 668 1289 78 >18.5
m2 642 5065 274 >19.4
w2 593 1389 97 >18.8
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.166 in the direction of the burst
(Schlegel et al. 1998).